are mechanically-driven bioreactors. As a consequence of the rocker movement with the bag(s) that contains the medium and the cells, a wave is induced. The energy input is highest with the minimal working volume, maximum angle and maximum rocking rate. Through the permanent renewal of the medium surface in the bubble-free surface aeration (see surface aeration), the foam formation is negligible. The largest wave-mixed bioreactors (see wave bioreactor system) have a bag volume of 1000 L which corresponds with a working volume of 500 L.